ReceiveTempSMS
/
Sweden-Number
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

plugplay: Broadcast WM_DEVICECHANGE message asynchronously. 

It may otherwise trigger a nasty race condition, where:

1) For explorer.exe to register the CLSID_ShellWindows classes, it
   needs RpcSS service to be started,

2) services.exe may start WinePlugPlay service group first, waiting for
   its startup to complete,

3) during startup and early device enumeration, hidclass.sys may call
   IoSetDeviceInterfaceState, which calls plugplay_send_event [1],

4) plugplay_send_event tries to broadcast a WM_DEVICECHANGE message with
   BSF_QUERY, waiting for the individual threads to reply,

5) which times-out because window threads are waiting on explorer.exe
   to create its desktop window and reply to the WM_NULL SendMessage.

This happens more likely as there is threads with message queues
being started, each waiting on the desktop window to reply. Usually
explorer.exe is able to reply to some messages with the implicit
message processing while creating its window, but not all of them.

[1] Not completely sure how, it looks like some RPC too, but before
    RpcSs is started?

Signed-off-by: Rémi Bernon <rbernon@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>
This commit is contained in:
Rémi Bernon 2021-02-15 20:42:00 +01:00 committed by Alexandre Julliard
parent 1b10b88d32
commit f5ca06016d
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
programs/plugplay/main.c
View File

@ -142,8 +142,8 @@ void __cdecl plugplay_send_event( DWORD code, const BYTE *data, unsigned int siz
struct listener *listener;
struct event *event;
BroadcastSystemMessageW( BSF_FORCEIFHUNG | BSF_QUERY, NULL, WM_DEVICECHANGE, code, (LPARAM)data );
BroadcastSystemMessageW( BSF_FORCEIFHUNG | BSF_QUERY, NULL, WM_DEVICECHANGE, DBT_DEVNODES_CHANGED, 0 );
BroadcastSystemMessageW( 0, NULL, WM_DEVICECHANGE, code, (LPARAM)data );
BroadcastSystemMessageW( 0, NULL, WM_DEVICECHANGE, DBT_DEVNODES_CHANGED, 0 );
EnterCriticalSection( &plugplay_cs );